Edited speeches from the winners of best cinematography, editing, hair and makeup and live action short will be played later in the ceremony.
The signatories, who also include Roger Deakins, have urged the Academy to reverse the decision.
What is the issue?
On 11 February the Academy emailed members to say that, in order to keep the show down to three hours, they would be presenting four awards during commercial breaks.
Their winning speeches would then be aired later in the broadcast in edited form.
It is hoped the shorter ceremony will stop falling viewers for the ceremony.
"Viewing patterns for the Academy Awards are changing quickly in our current multi-media world, and our show must also evolve to successfully continue promoting motion pictures to a worldwide audience," the email said.
What has the reaction been?
Russell Crowe called it "a fundamentally stupid decision" and too "dumb for words".
Double Oscar winner Alfonso Cuarón, whose film Roma is nominated for 10 Oscars this year including cinematography was one of the first to object.
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